FIG. 5 is a cross-sectional view showing an example of a conventional electromagnetic operating device for a switch disclosed in Japanese Laid-Open Patent Publication No. 2004-165075, which is roughly configured as follows:
In FIG. 5, the electromagnetic operating device includes a fixed core unit 10, a moving core unit 40, drive coils 20 and 30, and permanent magnets 50. The fixed core unit 10 includes a first core 11 to a forth core 14; the first core 11 includes a ring-shaped core section 11a and engaging sections 11e; the engaging sections 11e are formed between the ring-shaped core section and projecting sections 11f that project in X directions from sections that face each other in the X directions in the X-Y-Z triaxial coordinate system of the ring-shaped core section 11a. The second core 12 has the same frame as that of the first core.
The third core 13 and the fourth core 14 have their own split core sections. The first core 11 and the second core 12 are arranged in such a way that their ring-shaped core sections face each other maintaining there between a predetermined gap in a Y direction; the third core 14 and the fourth core 15 are arranged facing each other in the X directions so as to form a combined core unit of each of the split core sections; and the combined core unit is disposed in the gap between the first core 11 and the second core 12 that face each other so that, viewed from Y directions, the combined core unit and the ring-shaped core sections of the first core 11 and the second core 12 overlap with each other.
A container section 10b is formed being enclosed by the ring-shaped core sections of the first core 11 and the second core 12 and a ring-shaped core section formed of the split core sections of the third core 13 and the fourth core 14.
The moving core unit 40 includes a moving core 41 formed into a rectangular block by laminating magnetic steel sheets and support shafts 45 and 46 that are fixed to the moving core 41 and made of a non-magnetic material. The permanent magnets 50 each are formed into a thick rectangular plate, for example, and magnetically attached onto the top and bottom faces of the moving core 41 and pressed thereonto with a support member 60 that covers outer faces of the permanent magnets 50.
Moreover, coils 20 and 30 are wound around bobbins 21 and 31, respectively, and the bobbins 21 and 31 are engaged in the engaging sections 11e of the first core 11, and their positions are thereby restricted in X and Z directions.
The moving core 41 is held in the container section 10b and supported by the support shafts 45 and 46 that are supported by bearings 80 provided in the fixed core unit, so that the moving core unit 40 is enabled to move in Z directions by energizing the coils 20 and 30.
Patent Document 1: Japanese Laid-Open Patent Publication No. 2004-165075 (FIG. 1-FIG. 7)